You are the parent.
She is the daughter.
It is not her choice who you marry. Of course you want her to be happy with the man you chose to spend your life with but ultimately, this is between you and him. You will be living with him and loving him. NOT YOUR DAUGHTER.
Don't EVER give in to ultimatums. They do nothing other than teach your daughter she has control over you and you will do anything she wants if she threatens you enough. That needs to stop. She is an adult and so are you.
Marry the guy, love him and start standing up for yourself. You are not a doormat.
